Wiring for ARB compressor in the rear
 

It's time for me to add an air compressor. My use cases are both off-roading and cycling. I've gone between a Genuine Integrated Air Compressor paired with an ARB Aluminum Compressor Air Tank (for speed) and the ARB Brushless Twin (for even more speed). I have 32.6" tires now, with aspirations of 35's in my future. I've ruled out a portable compressor or a compressor in the engine bay, both due to the increased hassle. I can't imagine my spouse bothering with opening up the Defender's hood to pump up mountain bike tires. But something integrated or on-board in the rear that is push-button-simple would work. I like the air-down capability of the genuine compressor and the speed of the ARB. The thing holding me back from the ARB option is knowing how to wire it up to a power source in the rear that can handle the ~80 Amps that the ARB compressor draws. Can anyone point me to a source where I can learn how to do this? I understand from Simon@PowerfulUK and Justin@Lucky8 videos that I can pull power from the fuse box in the back, but I haven't found anyone explaining or demonstrating how to a novice. I'm in a 2023 P300 110, btw. Thanks for any help.

See my thread:
https://landroverforums.com/forum/20...output-107960/

The Viair 485c is only drawing max 28 amp. , direct connected on the main battery.

Be careful with the dual ARB brushless. In our testing, it got very, very hot. So hot in fact that it caused damage to a SMC (composite) hood under which it was mounted. It was very fast though.

Also, the harnesses that come with the ARB compressors are, not great. On the normal dual compressor model, the harness combines the two harness ground wires into a single ground wire after the connector. It also has a separate tiny gauge ground wire for the switch illumination circuit. ARB instructs you to connect both of these wires to the same negative terminal on the battery.

On mine, the splice in the middle of the harness was NOT SOLDERED. This caused one of the compressors to intermittently lose its ground, and it tried to go through the tiny illumination ground wire instead. No bueno. The tiny wire turned into a heating element, melted its insulation and was smoking. Doing some research, it seems that some other people have run into this same problem. After nearly catching my truck on fire, I took the harness apart, soldered that combined ground splice and removed the tiny black wire from the circuit since I don't use the ARB switch at all. Everything works as expected now thankfully.

In any case, with the amount of amperage we're talking about, I would only do a direct connection to the battery. There are definite rules as fair as Volage/Amperage over distance with regards to wire gauge that you do NOT want to violate (see my smoking wire above as an example). As far as the mounting location, have you considered perhaps mounting the compressor under the hood and then mounting an air chuck connector on the bumper or some other accessible area where you don't have to pop the hood? Routing flexible air lines is a LOT less risky than routing high amperage wire throughout the cabin of your nice Defender.

Just get the Land Rover integrated compressor.

I have 33’s. Heavily offroad. It’s fine. It’s not as fast as a big ARB, which my friends have and yes, are slightly faster, but the packaging and ease of use is far superior in my opinion. I also like how I don’t have to kneel at every wheel. Just set PSI, hook it up to a wheel, walk away.

It does take a slightly long time to air all the way up to 47 or 50 PSI for heavy load setting, so usually after an offroad trip, when I get back to the highway I air up to the lower comfort pressure. Air all the way back up when I get home.

Either way, for bike tires, this 10000% is your answer.

Oh - and also - if you get it, buy these quick release chucks so you don’t have to screw the hose on the tire valve every time. It just screws on to the end of the air hose. Then you can quick release on and off the tire valves at each wheel. (I’m talking vehicle tire valves, not skinny road bike tire valves)

The inbuilt is not as fast as the single compressor ARB.

I don’t have a wired in compressor. Just the toolbox mounted ARB with my tire repair kit and deflators all in one place. I use it for other things like winterizing pipes, other vehicle, and the like.

Not at all useful for pumping stuff up without opening the hood so not what you’re looking for.

I saw a cool under hood mount for the ARB recently. It uses the faux air vent on the side as the spot for the air outlet. Very nifty idea.

Just add an RF switch/relay controlled by the garage door opener buttons on the mirror and you’d have a very handy, low cost, clean setup with no hood opening ever needed.

Arb all the way
 

I have both the factory one and now an ARB and hands down the ARB is the way to go. The factory took 47 minutes to fill all four tires from 20psi to 50psi. The new ARB took 8 minutes total. I have a @Saltek Motorsports mount in the engine bay and it has held up to some serious off roading. No problems whatsoever on all of there parts. And a lot easier to wire up there.
https://cimg2.ibsrv.net/gimg/landrov...4c44a7a36.jpeg
https://cimg4.ibsrv.net/gimg/landrov...d297ea0fd.jpeg

Thank you all for your responses.

Very nice. How many tires will your 2 gallon tank fill up on its own? I like the tank add-on for the idea that it would speed up the overall process using a smaller compressor. I'm also wondering if the JLR integrated compressor would be comparable performance to the Viair 485c that you chose.

Thank you for the words of caution about running wire gauge. Perhaps I should reconsider the hood option, coupled with an externally accessible switch and outlet hose as others have mentioned.

Agreed that the choice is very simple if bikes were my only need. You point out other compelling benefits of the integrated compressor.

Yeah, great idea. I presume they just hacked the air vent with a knife. Or another implementation I've seen that mounts the air outlet on a Saltek ditch light bracket.

Now this I gotta look into!

47 minutes! I wonder how much a pre-filled 1 gallon tank would speed that up.

To fill the 2 gallon airtank to 200psi wil take under 5 minutes, so before going back on road I start with a full tank.
The first tire inflate of course the quickest, the Viair kicks in at 165psi and keeps running after that.
So 4 tires 32" from 20psi to 34psi ( light load ) under 5 minutes.

Don't compare the Landrover compressor with the Viair 485c gen2 constant duty 200psi for 1 hour continue.
( The 485C Gen 2 air compressors deliver game-changing performance, delivering 1-hour of performance at 200 PSI before needing rest. This unit is the premium choice for industrial and automotive applications.

I’ve got the Saltek under hood mount with the single ARB. If you’re a newbie - be careful wiring these up. They pull a lot of current. Even the single ARB is fast. 30 psi —> 45 in 15-20 secs, maybe less. I was able to wire mine to my existing sPOD controller - it goes handles 30 amps, and I’m right at the limit.